This invention relates to a cartridge type coating system employing a plural number of paint cartridges, for example, a plural number of paint cartridges of different colors, which are adapted to be replaceably attached to a sprayer unit of the coating system.
Generally, coating systems which are in use for coating automotive vehicle bodies or the like are largely constituted by a coating action mechanism like a coating robot, and a sprayer unit which is mounted on the coating action mechanism. Coating systems of this sort can perform coating operations automatically, as paint is sprayed by a sprayer unit which is operated according to programed operational procedures. In this connection, the coating systems of this class are required to be able to cope with a larger number of paint colors and at the same time to meet demands for reductions in the amount of paint which has be discarded at the time of changing the paint color and also in the amount of thinner which is consumed in cartridge washing operations.
As well known in the art, in an attempt to meet the requirement or demands for reductions of the amounts of paint discard and thinner consumption and for capability of handling a larger number of colors, there have thus far been developed a number of cartridge type coating systems (e.g. as disclosed in Japanese Laid-Open Patent No. H8-229446). Cartridge type coating systems of this sort employ a number of paint cartridges which are filled with paint of different colors and adapted to be replaceably mounted or loaded on a sprayer unit.
For instance, a cartridge type coating system is largely constituted by a housing which is provided with a sprayer mount portion on the front side and a cartridge mount portion on the rear side thereof, and a sprayer unit which is mounted on the sprayer mount portion of the housing and comprised of an air motor with a rotational shaft and a rotary atomizing head which is mounted on a front end portion of the rotational shaft of the air motor. Further, formed axially and internally of the rotational shaft of the sprayer unit is a feed tube passage hole having fore and rear ends thereof opened into the sprayer unit and cartridge mount portion of the housing, respectively.
Further, in the case of above-mentioned Japanese Laid-Open Patent No. H8-229446, the cartridge type coating system is arranged to replaceably mount on the housing a number of separate paint cartridges of different colors. Each paint cartridge is constituted by a casing having a container which is internally filled with paint, and a feed tube which is extended axially forward from a fore end of the container. The container of the paint cartridge is replaceably set on the cartridge mount portion of the housing, with the feed tube passed into the above-mentioned feed tube passage hole on the side of the housing.
Further, in the cartridge type coating system according to the above-mentioned Japanese Laid-Open Patent No. H8-229446, the casing of the cartridge is provided with a movable partition wall which divides the container into a paint chamber in communication with the feed tube and a paint-extruding air chamber, and an air passage on the side of the paint cartridge, which supplies extruding air to the extruding air chamber. Further, an extruding air passage is provided on the part of the housing for communication with the extruding air passage on the side of the paint cartridge. Thus, extruding air is circulated to the extruding air chamber through the extruding air passage on the side of the housing and the extruding air passage on the side of the paint cartridge to displace the movable partition wall in a direction of extruding paint in the paint chamber toward the feed tube and the rotary atomizing head.
With the cartridge type coating system which is arranged in the manner as described above, one paint cartridge to be used in a coating operation is selected from a plural number of paint cartridges of different colors, and set in position on the cartridge mount portion of the housing. Then, air is supplied to the extruding air chamber of the cartridge at a suitable rate to discharge paint in the paint chamber of the cartridge toward the rotary atomizing head through the feed tube. Consequently, paint is sprayed toward a work piece by the rotary atomizing head.
The paint color can be changed simply by replacing the paint cartridge by another paint cartridge which is filled with paint of a desired color, without necessitating to discard paint and thinner on each color change.
On the other hand, the paint cartridge, which has been consumed in a previous coating operation and removed from the housing by the color changing operation, is returned to a cartridge holder table for paint replenishment.
The cartridge type coating system by the above-described prior art, employing a plural number of paint cartridges of different colors, has made it possible to change the paint color simply by replacing the paint cartridge on the housing by a cartridge of a different color, without requiring to wash interior portions of the paint cartridge or feed tube.
However, in the case of a cartridge type coating system as described above, sometimes the whole system is put at rest for a long period of time for the sake of maintenance and serve or for carrying out repairing work. On such an occasion, it has been necessary to wash interiors of paint cartridges and feed tubes to prevent separation or solidification of paint.
In the case of the cartridge type coating system of the above-described prior art without cartridge washing functions, paint cartridges have to be washed manually despite the fact that the cartridge washing job is troublesome and time consuming.
In view of the above-discussed problems with the prior art, it is an object of the present invention to provide a cartridge type coating system, which can wash away deposited paint from paint cartridges within a shortened period of time in such a manner as to improve the efficiency of cartridge washing operations to a considerable degree.
In order to solve the above-discussed problems with the prior art, the present invention contemplates to provide improvements in a cartridge type coating system which basically includes: a paint sprayer unit, a plural number of paint cartridges each detachably connectable to the sprayer unit to supply paint thereto from an internal paint source, and a paint replenisher detachably connectable to an empty paint cartridge for replenishing paint thereinto.
According a feature of the present invention, there is provided a cartridge type coating system which comprises: a plural number of paint cartridges each constituted by a casing having a container and a feed tube extended forward from a fore end portion of the container, a movable partition wall provided in the container and dividing same into a paint chamber in communication with the feed tube and a paint-extruding liquid chamber, a normally closed paint valve provided in the casing and adapted to be opened at the time of supplying paint from the paint chamber to the sprayer unit through a paint passage in the feed tube or at the time of replenishing paint into the paint chamber, an extruding liquid passage for circulating the extruding liquid to and from the extruding liquid chamber, a wash fluid passage for supplying a wash fluid to the paint chamber, and a normally closed wash fluid valve provided in the wash fluid passage and adapted to be opened at the time of supplying the wash fluid to the paint chamber; and a paint replenisher constituted by a replenishing stool on which the paint cartridge is set at the time of replenishing paint into the paint chamber, a replenishing valve connected to the replenishing stool and adapted to replenish paint into the paint chamber of the paint cartridge through the paint passage in the feed tube while the paint valve is in an open state, an extruding liquid feed/discharge valve connected to the replenishing stool and adapted to feed or discharge the extruding liquid to or from the extruding liquid chamber of the paint cartridge through the extruding liquid passage while the paint valve is in an open state, and a wash fluid supply valve connected to the replenishing stool and adapted to supply the wash fluid to the paint chamber through the wash fluid passage while the wash fluid valve is in an open state.
With the arrangements just described, before starting a coating operation, a paint cartridge which has been replenished with paint on a replenishing stool of the paint replenisher is picked up therefrom and attached to the sprayer unit of the coating system. In that state, a paint-extruding liquid is supplied to the extruding liquid chamber of the cartridge, causing the movable partition wall to move forward toward the feed tube. Whereupon, paint in the paint chamber of the cartridge is spurted toward the sprayer unit from the feed tube and sprayed by the sprayer unit.
In this case, during a coating operation, paint in the paint chamber of the cartridge may tend to flow out through the wash fluid passage on the side of the paint cartridge. However, since the wash fluid valve is normally closed to block the wash fluid passage, it can prevent paint leaks through the wash fluid passage.
Next, in the case of replenishing paint into a paint cartridge, a consumed paint cartridge is detached from the sprayer unit, and set on and connected to a replenishing stool of the paint replenisher. In this state, extruding liquid in the extruding liquid chamber of the cartridge is discharged through the extruding liquid feed/discharge valve. Then, the feed tube of the cartridge is brought into communication with a paint supply side by the replenishing valve. Whereupon, paint is sucked into the paint chamber of the cartridge through the paint passage in the feed tube.
In a case where there is still some time before a replenished paint cartridge is used in a next coating operation, the replenished paint cartridge is left on the replenishing stool in the connected state, holding the feed tube of the cartridge in communication with the paint supply side through the replenishing valve. In this state, an extruding liquid is supplied to the extruding liquid chamber of the cartridge, pushing out paint in the paint chamber through the movable partition wall by the extruding liquid feed/discharge valve for return to the paint supply side. In a next phase, the extruding liquid in the extruding liquid chamber of the cartridge is discharged by the extruding liquid feed/discharge valve to suck paint into the paint chamber again. In this standby state, the paint inhaling and exhaling actions to and from the paint chamber (respiratory paint circulation) are repeated to prevent separation and sedimentation of pigment components of the paint.
Further, in order to wash the paint chamber and interior passages of a paint cartridge, the cartridge is detached from the sprayer unit and set on a replenishing stool of the paint replenisher. In this state, a wash fluid is supplied to the paint chamber by the wash fluid supply valve and circulated through the feed tube to wash away paint from the paint chamber and feed tube of the cartridge.
According to a preferred form of the present invention, the replenishing valve of the paint replenisher is constituted by a paint feed/discharge valve adapted to be opened at the time of supplying paint from a paint supply source to the paint chamber of the cartridge or at the time of returning paint in the paint chamber to the paint supply source, and a waste liquid discharge valve adapted to be opened at the time of supplying the wash fluid to the paint chamber of the cartridge.
With the arrangements just described, a paint cartridge to be replenished with paint is set on a replenishing stool of the paint replenisher. In that state, the paint feed/discharge valve is opened in order to supply paint to the paint chamber of the cartridge from a paint supply source or in order to discharge paint from the paint chamber of the cartridge for return to the paint supply source. On the other hand, when the waste liquid discharge valve is opened for washing the paint cartridge, the wash fluid which has been supplied to the paint chamber of the cartridge is discharged through the paint passage in the feed tube along with discard paint.
According to the present invention, the above-mentioned extruding liquid feed/discharge valve of the paint replenisher is constituted by an extruding liquid supply valve adapted to be opened at the time of supplying the extruding liquid to the extruding liquid chamber of the cartridge, and an extruding liquid discharge valve adapted to be opened at the time of discharging the extruding liquid from the extruding liquid chamber of the cartridge.
With the arrangements just described, in a case where there is still some time before a replenished paint cartridge is used in a next coating operation, the paint cartridge is left on the replenishing stool in a connected state. In this state, the extruding liquid supply valve is opened and an extruding liquid is supplied to the extruding liquid chamber of the paint cartridge, pushing out paint in the paint chamber through the movable partition wall. On the other hand, when the extruding liquid discharge valve is opened, the extruding liquid is discharged from the extruding liquid chamber of the cartridge, and as a consequence paint is sucked into the paint chamber of the cartridge from the paint supply source in step with the discharge of the extruding liquid.
According to the present invention, the wash fluid supply valve of the paint replenisher is constituted at least by a wash thinner supply valve adapted to supply wash thinner to the paint chamber of the cartridge or by a wash air supply valve adapted to supply wash air to the paint chamber of the cartridge.
In a case where one paint cartridge is used commonly for paint of different kinds or colors, for instance, it becomes necessary to wash the paint cartridge before putting a coating line at rest for a long period of time. For this purpose, the paint cartridge is set on and connected to a replenishing stool of the paint replenisher. In this state, the wash air supply valve is opened, whereupon wash air is supplied to the paint chamber of the cartridge to push out and discharge paint residues from the paint chamber and feed tube of the cartridge. On the other hand, when the wash thinner supply valve is opened, wash thinner is supplied to the paint chamber of the cartridge to wash away deposited paint from the paint chamber and feed tube.
According to the present invention, the extruding liquid passage and the wash fluid passage of the paint cartridge are separately provided in the casing.
With the arrangements just described, the wash fluid running through the wash fluid passage can be prevented from mixing into the extruding liquid flowing through the extruding liquid passage.
According to the present invention, the extruding liquid passage and the wash fluid passage of the paint cartridge are provided with a common inlet port, and the wash fluid valve is arranged in the form of a change-over valve adapted to switch the common inlet port either to the extruding liquid passage or the wash fluid passage.
With the arrangements just described, a paint cartridge to be refilled with paint is set on and connected to a replenishing stool of the paint replenisher. In this state, the common inlet port is switched to the side of the extruding liquid passage by the change-over valve and communicated with the extruding liquid chamber of the cartridge through the extruding liquid passage. Therefore, the extruding liquid allowed to flow into or out of the extruding liquid chamber. On the other hand, when the common inlet port is switched to the side of the wash fluid passage by the change-over valve, it is brought into communication with the paint chamber of the paint cartridge through the wash fluid passage to feed the extruding liquid to the paint chamber as a wash fluid thereby to wash away deposited paint from the paint chamber and feed tube of the cartridge.
According to the present invention, the wash fluid valve of the cartridge is arranged in the form of a check valve adapted to be opened when the wash fluid is circulated toward the paint chamber through the wash fluid passage and closed when paint is flowing toward the feed tube from the paint chamber.
With the arrangements just described, after a paint cartridge is set on and connected to a replenishing stool of the paint replenisher, the check valve is opened when a wash fluid is circulated through the wash fluid passage in the direction toward the paint chamber. In this case, the wash fluid is introduced into the paint chamber to wash away deposited paint therefrom. On the other hand, at the time of delivering paint in the paint chamber through the feed tube, the check valve is closed to block reverse paint flow toward the wash fluid passage from the paint chamber. As a result, paint leaks through the wash fluid passage can be prevented by the check valve.
According to the present invention, the paint chamber of the cartridge is formed as a space of a substantially circular shape in cross-section, and the wash fluid passage of the cartridge is opened tangentially toward inner periphery of the paint chamber.
With the arrangements just described, the wash fluid from the wash fluid passage is introduced into the paint chamber in a tangential direction with respect to the inner periphery of the paint chamber. Therefore, thanks to the vortices of the wash fluid which are formed within the paint chamber, paint in the paint chamber can be washed off effectively in a more efficient manner.
According to the present invention, a spacer member or members are provided on a bottom surface of the paint chamber or on the movable partition wall to leave a gap space for circulation of the wash fluid between the bottom surface of the paint chamber and the movable partition wall when the latter is moved toward the feed tube.
With the arrangements just described, the breadth of the washing space of the paint chamber can be reduced by a displacement of the movable partition wall toward the feed tube. On such an occasion, a gap space suitable for circulation of a wash fluid is secured by the spacer member between a bottom surface of the paint chamber and the movable partition wall to ensure an efficient washing operation.
According to the present invention, the sprayer unit is mounted on a coating action mechanism at the time of performing a coating operation, and an extruding liquid passage is provided in the coating action mechanism for communication with the extruding liquid passage on the side of the paint cartridge, the extruding liquid passage on the side of the coating action mechanism being connected to an extruding liquid feeder to send an extruding liquid to the paint cartridge attached to the sprayer unit.
With the arrangements just described, a replenished paint cartridge is attached to the sprayer unit prior to a coating operation. Then, the extruding liquid from the extruding liquid feeder is supplied to the extruding liquid chamber of the cartridge through the extruding liquid passage on the side of the coating action mechanism and the extruding liquid passage on the side of the paint cartridge, thereby displacing the movable partition wall forward to push paint in the paint chamber forward and spurt the paint to the rotary atomizing head of the sprayer unit through the feed tube. In the meantime, the coating action mechanism is put in action to perform a predetermined coating operation.
According to the present invention, there is provided a cartridge type coating system which is characterized in that: the paint cartridges are each provided with a common inlet port opened in an outer peripheral portion of the container, an extruding liquid passage connecting the common inlet port with the extruding liquid chamber, a wash fluid passage connecting the common inlet port with the paint chamber, and a change-over valve adapted to switch the common inlet port either to the extruding liquid passage or to the wash fluid passage; and the paint replenisher is provided with a selector valve having the inlet side thereof connected to the extruding liquid feed/discharge valve and the wash air supply valve and the outlet side thereof connected to the replenishing stool and adapted to connect either the extruding liquid feed/discharge valve or the wash air supply valve selectively to the common inlet port of the cartridge.
With the arrangements just described, a paint cartridge to be refilled with paint is set on and connected to a replenishing stool of the paint replenisher. In this state, if the change-over valve is switched to the side of the extruding liquid passage, the common inlet port is communicated with the extruding liquid chamber of the cartridge through the extruding liquid passage, and the extruding liquid from the extruding liquid feed/discharge valve is allowed to flow into or out of the extruding liquid chamber.
On the other hand, when the change-over valve is switched to the side of the wash fluid passage, the common inlet port is communicated with the paint chamber of the cartridge through the wash fluid passage, whereupon wash air from the wash air supply valve is introduced into the paint chamber to purge paint from the paint chamber and the feed tube. Further, by supplying extruding liquid from the extruding liquid feed/discharge valve to the paint chamber as a wash fluid, deposited paint in the paint chamber and the feed tube can be washed away by the supplied extruding liquid.
According to the present invention, there is provided a cartridge type coating system which is characterized in that the cartridge gripper mechanism is provided with a gripper for gripping the paint cartridge, and a wash fluid passage formed in the gripper and adapted to be connected to the wash fluid passage on the side of the cartridge when the latter is gripped on the gripper, an upstream end of the wash fluid passage in the gripper being connected to a wash fluid supply valve which supplies a wash fluid to the paint chamber of the cartridge.
With the arrangements just described, by means of the cartridge gripper mechanism, a paint cartridge which is attached to the sprayer unit can be gripped and removed therefrom and then set on a replenishing stool of the paint replenisher. In a case where the paint chamber of the cartridge is to be washed, the paint cartridge is left in the gripped state, with the wash fluid passage on the side of the gripper connected with the wash fluid passage on the side of the paint cartridge. In this state, wash fluid from the wash fluid supply valve can be introduced to the paint chamber through the wash fluid passage on the side of the gripper and the wash fluid passage on the side of the paint cartridges to wash away deposited paint from the paint chamber and feed tube of the cartridge.
According to the present invention, there is provided a cartridge type coating system which is characterized by the provision of a cartridge gripper mechanism for gripping and transferring a paint cartridge to and from the sprayer unit and the paint replenisher, the cartridge gripper mechanism being provided with a pilot air passage for supply pilot air to the wash fluid valve when the cartridge is gripped on the cartridge gripper mechanism.
With the arrangements just described, by means of the cartridge gripper mechanism, a paint cartridge which is attached to the sprayer unit can be gripped and removed therefrom, and then set on a replenishing stool of the paint replenisher. In a case where the paint chamber of the cartridge is to be washed, the paint cartridge is left in the gripped state. In this state, as soon as pilot air is supplied to the wash fluid valve of the cartridge through the pilot air passage on the side of the cartridge gripper mechanism, the wash fluid valve is opened, supplying a wash fluid to the paint chamber and thereby washing away deposited paint from the paint chamber and the feed tube of the cartridge.